This application relates to the field of community antenna television (CATV) systems and more specifically to arrangements for customer interfaces used in such CATV systems.
In CATV systems, a system operator broadcasts television programs through a fiber optic network tree from a head-end to a multitude of network nodes, and then through coaxial cable network trees from each node to a respective multitude of network terminations at customer locations. A central power supply provides AC power to the CATV system, and the power is distributed through a conductor tree to the nodes and then through the coaxial network trees. The AC power is used to provide power to the nodes and to in-line signal amplifiers in the coaxial network trees. In the nodes and amplifiers, the AC power is converted to DC power to operate various electronic equipment.
The optical fiber tree may extend up to 100 Km and the coaxial system may extend many more kilometers to customer locations. In CATV systems, the head-end may be connected to hundreds of nodes, and each node may be connected to hundreds of customers.
Equipment is being developed to allow cable television networks to also be used for providing other communication services such as telephone, security monitoring, and Internet connection. Customer interface units at customer locations share a few available channels for communication through the coaxial cable network. Additional optical fiber network trees are provided to transport return signals from the nodes back to the head-end and to provided additional bandwidth for communications from the head-end to the node.
It is an object of the invention to provide user interface apparatus to allow existing CATV systems to provide additional data services such as phone, Internet, and security monitoring.
It is another object of the invention to provide user interface apparatus for new CATV systems which reduce energy consumption.
In the invention, the user interface apparatus consists of an inside unit and an outside unit. The inside unit is connected to standard consumer power (e.g. 110V) so that the interface draws less power from the CATV power distribution network. The power provided from the standard customer power is isolated from the power distributed by the CATV network.
In one embodiment of the invention, power drawn from standard consumer power by the inside unit is stepped down in voltage and transferred to operate equipment in the outside unit for signal processing.
In another embodiment of the invention customer service equipment and signal processing is provided by the inside unit.
In existing CATV systems, the central power supply and the conductor tree extending to the nodes are typically designed to provide power only for existing nodes and amplifiers and possibly for some expected system expansion. The power required for operating user interfaces required to provide additional communications services, for hundreds of customers for each node, could be 1-3 orders of magnitude more than existing CATV power requirements. The invention allows adding user interface apparatus to existing systems without providing a new high power AC distribution system to the CATV system.
For new CATV systems it is more energy efficient to provide power for user interface apparatus from the customer""s standard consumer power. A complete, high-current, consumer power distribution system already exists to provide customers with electrical power. The resistances through this high-current network, are relatively small since the consumer power system is economically designed for large currents. It would be redundant and inefficient to provide another power distribution system for customer interface equipment. The CATV power distribution system is typically less energy efficient than the standard consumer power system, because it is economically designed for much smaller loads over a large area.
Other alternatives and advantages of applicant""s inventions will be disclosed or become obvious to those skilled in the art by studying the detailed description below with reference to the following drawings which illustrate the elements of the appended claims of the inventions.